Mower deck lift system with transport lock

ABSTRACT

A mower deck lift system includes a transport lock for locking the mower deck in a transport position, a height of cut control knob connected to a height of cut cam having a plurality of mower deck height settings, and a height of cut pawl movable to engage or disengage the height of cut cam at each mower deck height setting. A transport lock crank may be locked in a transport position preventing the height of cut pawl from engaging the height of cut cam, or unlocked to allow the height of cut pawl to engage the height of cut cam. A transport lock indicator integrated into the height of cut control knob is connected to the transport lock crank, and is movable with the transport lock crank between the transport position and an unlocked position.

This is a divisional application and claims priority based on U.S.application Ser. No. 11/674,840, filed Feb. 14, 2007, and entitled,MOWER DECK LIFT SYSTEM WITH TRANSPORT LOCK under 35 U.S.C. 119(e).

FIELD OF THE INVENTION

The present invention relates generally to height adjustable mowercutting decks, and specifically to a mower deck lift system with atransport lock to hold the mower deck at a transport position.

BACKGROUND

Vegetation cutting implements such as mower cutting decks are typicallycarried by self propelled vehicles or lawn tractors having mechanismsallowing adjustment of the decks between a range of heights above groundlevel. Ordinarily, the range extends between a position at or below thelowest available cut height to a position at or above the highestavailable cut height. Adjustment to a position below the cut heightrange is frequently preferred for ease in removal of the deck from thevehicle because the deck is that much closer to the ground surface.Adjustment above the cut height range may permit the deck to clearobstacles encountered while traveling across the ground. This maximumheight position may be referred to as the deck transport position.

Adjustment of the cutting deck height may be accomplished by variousmechanisms including hand-operated levers and bars positioned in thevicinity of the mower's operator station. The mechanisms require anoperator to either push or pull on a lever or bar to adjust the deckheight. Pedal actuated mechanisms also are used to adjust cutting deckheight relative to the mower frame. Pedal actuated mechanisms mayinclude a handle or other hardware which automatically locks the deck ina given position upon full actuation of the pedal. U.S. Pat. No.4,120,136 for “Implement Supporting and Lifting Linkage”; U.S. Pat. No.5,138,825 for “Riding Mower Having a Pedal Operated Height AdjustmentMechanism, Air Assisted Discharge, and Improved Hydrostatic ShiftLinkage”; U.S. Pat. No. 5,187,925 for “Mower Deck Lift System HandleMechanism”; U.S. Pat. No. 5,351,467 for “Height Adjustment Mechanism forRiding Mower Cutting Deck”; U.S. Pat. No. 5,381,648 for “Mower DeckHeight Adjustment Mechanism”; U.S. Pat. No. 5,797,252 for “Height of CutAdjustment Mechanism”; U.S. Pat. No. 5,816,033 for “Riding Lawn MowerIncluding a Mower Deck Height Control Mechanism”; U.S. Pat. No.5,946,893 for “Lawn Mower Having Cutter Deck Motion Coupled to MowerWheel Motion”; U.S. Pat. No. 6,427,430 for “Pedal Lift System for LawnTractor Mower Deck”; U.S. Pat. No. 6,494,028 for “Deck Lift Apparatusfor Riding Mower”; U.S. Pat. No. 6,588,188 for “Foot Lift Cutter DeckMower Units” and U.S. Pat. No. 6,837,032 for “Pedal Actuated HeightAdjustment Mechanism for a Mower Cutting Deck” provide examples of mowerdeck lifting mechanisms.

A mower deck lift system is needed that provides convenient visualfeedback to the operator if the transport lock is engaged. A mower decklift system is needed that allows the operator to quickly and simplyelect whether or not to engage the transport lock. A mower deck liftsystem is needed that maintains the mower deck at the same height of cutsetting after the mower deck is raised to the transport position.

SUMMARY OF THE INVENTION

A mower deck lift system with a transport lock provides convenientvisual feedback to the operator if the transport lock is engaged. Themower deck lift system allows the operator to quickly and simply electwhether or not to engage the transport lock. The mower deck ismaintained at the same height of cut setting after the mower deck israised to the transport position.

The mower deck lift system includes a height of cut control knob movableto a plurality of positions, each position corresponding to a cuttingheight. A height of cut pawl is attached to the height of cut controlknob and pivots to engage a height of cut cam to hold the mower deck ateach cutting height set with the control knob. A transport lock crank isbiased to a transport lock position preventing the height of cut pawlfrom engaging the height of cut cam, and a transport lock indicatorconnected to the transport lock crank provides visual feedback to theoperator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a mower deck liftsystem operated with a foot pedal, with a transport lock that is lockedin the transport position.

FIG. 2 is a perspective view of a first embodiment of a mower deck liftsystem operated with a foot pedal, with a transport lock that isunlocked.

FIG. 3 is a perspective view of the first embodiment of the transportlock that is locked in the transport position.

FIG. 4 is a perspective view of the first embodiment of the transportlock in the unlocked position.

FIG. 5 is a perspective view of a second embodiment of a mower deck liftsystem operated with an electro-hydraulic actuator, with a transportlock that is locked in the transport position.

FIG. 6 is a perspective view of a second embodiment of a mower deck liftsystem operated with an electro-hydraulic actuator, with a transportlock that is unlocked.

FIG. 7 is a top view of an embodiment of a height of cut control knoband transport lock indicator.

DESCRIPTION OF PREFERRED EMBODIMENTS

In a first embodiment shown in FIGS. 1-4, mower deck lift system 100 maybe operated with foot pedal 101 to raise and lower a mower deck. Theoperator may raise the mower deck by depressing the foot pedal, andlower the mower deck by releasing the foot pedal. The operator also mayuse transport lock 102 to lock the mower deck in the transport positiononce the mower deck is raised and the foot pedal is released.

In one embodiment, foot pedal 101 may be pivotably mounted on stationarypivot axis 103. Rod 104 may connect the foot pedal to height of cut pawl105. Turnbuckle 106 may be used to adjust the length of rod 104. Theheight of cut pawl engages a step on height of cut cam 107 correspondingto a selected cutting height. If the operator depresses the foot pedal,the height of cut pawl disengages the height of cut cam.

In one embodiment, height of cut pawl 105 may be bolted to rockshaft108. Depressing foot pedal 101 pivots the height of cut pawl and causesthe rockshaft to turn on its longitudinal axis in a direction to raisethe mower deck. Releasing the foot pedal allows the rockshaft to turn onits longitudinal axis in a direction to lower the mower deck, unlesstransport lock 102 is locked in the transport position.

In one embodiment, rockshaft 108 may be an extruded aluminum tube havinga longitudinal axis that is transverse to the primary axis of a grassmowing machine. The rockshaft may have internal channels 109-11 andopposing external flat surfaces 112-13 for locating and positioningmounting bolts. Several components may be bolted and removably attachedto the rockshaft without welding. This can reduce assembly cost andsimplify repair or replacement of components.

In one embodiment, mower deck lift system 100 may include height of cutcontrol knob 114 that may be turned manually to any of a number ofdifferent cutting heights indicated or marked on the height of cutcontrol knob. Tube 115 may connect the height of cut control knob toheight of cut cam 107. The tube may be inserted through and supported byheight of cut bracket 116 mounted to the frame of the grass mowingmachine. Each step on the outer circumference of the height of cut camcorresponds to a selected cutting height.

In one embodiment, left and right deck lift assist springs 117-18 maybias rockshaft 108 to turn on its longitudinal axis in a directiontending to raise the mower deck. The deck lift assist springs may beused because the weight of the mower deck urges the rockshaft to turn inthe opposite direction. The deck lift assist springs may be attachedbetween left and right spring cranks 119-20 bolted to the rockshaft, andleft and right stationary brackets 121-22 attached to the grass mowingmachine frame.

In one embodiment, the rear of the mower deck may be attached to thedeck lift mechanism with rear left and right deck hangers 123-24. Theupper ends of the rear left and right deck hangers are connected to leftand right deck lift cranks 125-26 bolted to rockshaft 108. The upperends of the rear left and right deck hangers may have slots or eyes thatare fastened to the deck lift cranks in such a manner that the rear ofthe mower deck can move up sufficiently to travel over an obstacle onthe ground. The upper ends of the rear left and right deck hangers areattached to the deck lift cranks at positions between about three inchesand about nine inches from the longitudinal axis of the rockshaft. Thedeck hangers may be configured to allow the mower deck to travelvertically about three inches to about five inches from the lowest andhighest cut heights. The lower ends of the rear left and right deckhangers are fastened to the rear of the mower deck on its left and rightsides. Drag links 127-28 may pivotably connect the rear left and rightdeck hangers to stationary pivot axis 103.

In one embodiment, the front of the mower deck may be attached to themower deck lift system with front left and right deck hangers 129-30.The upper ends of the front left and right deck hangers are pivotablyconnected to left and right cranks 131-32 on stationary pivot axis 103,at positions between about three inches and about nine inches from thepivot axis. Rods 133-34 connect the left and right cranks to pins 135-36which are bolted to rockshaft 108. The connection between rods 133-34and pins 135-36 may include slots or eyes that are fastened in such amanner that the front of the mower deck can move up sufficiently if anobstacle is encountered. Turnbuckles 137-38 may be used to adjust thelength of rods 133-34 to help level and/or adjust the mower deckposition.

In one embodiment, mower deck lift system 100 can raise and lower amower deck essentially vertically between a plurality of cutting heightsfrom about 1½ inches to about 5 inches. At cutting heights within thisrange, the mower deck lift system can effectively limit front-to-backtranslation of the mower deck to under about 10 mm.

In one embodiment, the mower deck may be locked in the transportposition automatically if the operator fully depresses foot pedal 101 toraise the mower deck to a maximum cut height such as 5 inches. Spring139 biases the transport lock to the transport position, so that themower deck automatically locks in the transport position. Once theoperator releases the foot pedal while the transport lock is locked inthe transport position, height of cut pawl 105 is prevented from movingback against height of cut cam 107.

In one embodiment, if the operator does not wish to lock the mower deckin the transport position (or wishes to release the mower deck from thetransport position), he or she may unlock the transport lock by pressingdown on transport lock indicator 140 with his or her hand. If theoperator releases the foot pedal while the transport lock is unlocked,height of cut pawl 105 can move back against a step on height of cut cam107, and the mower deck can descend to a specified cutting height. In analternative embodiment (not shown), the transport lock may engage onlyif the operator presses down on the transport lock indicator or anotherbutton.

In one embodiment shown in FIG. 7, transport lock indicator 140 providesa visual indicator showing if the transport lock is locked in thetransport position. The transport lock indicator may be integrated intoheight of cut control knob 114. The transport lock indicator may be atthe center of the height of cut control knob and may include a pointer145 to the height of cut settings listed on the height of cut controlknob. Additionally, the transport lock indicator may move between afirst position if the mower deck is locked in the transport position,and a second position if the mower deck is not locked in the transportposition. For example, in the first position, the transport lockindicator may extend above the center of the height of cut control knobto indicate that the mower deck is locked in the transport position. Inthe second position, in which the mower deck is not locked in thetransport position, the transport lock indicator may be at or near thetop surface of the height of cut control knob.

In one embodiment, transport lock indicator 140 may be connected by wireform 141 to transport lock crank 142. The wire form may be insertedthrough tube 115. Spring 139 may urge the transport lock crank to pivotin a direction to engage or block height of cut pawl 105, preventing theheight of cut pawl from engaging height of cut cam 107. The transportlock crank may be pivotably mounted to height of cut bracket 116.

In one embodiment, the mower deck may descend back to the same height ofcut setting after it is raised and/or locked in the transport position,unless the operator turns height of cut knob 114. Leaf spring 143 mayengage spring detent gear 144 to hold height of cut cam 107 at apreviously specified height of cut. The spring detent gear may beattached to and/or integral with the height of cut cam.

In a second embodiment shown in FIGS. 5-6, mower deck lift system 200includes electro-hydraulic actuator 201 instead of a foot pedal. Thehydro-electric actuator may be bolted to rockshaft 202, and may turn therockshaft by operating a push button or other control. In all otherrespects, the mower deck lift system operates the same as the firstembodiment, and has the same components and functions. If thehydro-electric actuator is used to turn the rockshaft to the transportposition, the transport lock may be locked in the transport position.Spring 203 urges transport lock crank 204 to pivot in a direction toengage or block height of cut pawl 205, preventing the height of cutpawl from engaging height of cut cam 206. Transport lock indicator 207may be connected to the transport lock crank by wire form 208. Theelectro-hydraulic actuator may be allowed to run for a maximum time,e.g., 5 to 15 seconds, to avoid overheating while the transport lock islocked in the transport position or unlocked.

Having described the preferred embodiment, it will become apparent thatvarious modifications can be made without departing from the scope ofthe invention as defined in the accompanying claims.

1. A mower deck lift system comprising: a height of cut control knobconnected to a height of cut cam having a plurality of mower deck heightsettings; a height of cut pawl movable to engage the height of cut camat each mower deck height setting; a transport lock crank that may belocked in a transport position preventing the height of cut pawl fromengaging the height of cut cam, or unlocked to allow the height of cutpawl to engage the height of cut cam; and a transport lock indicatorintegrated into the height of cut control knob and connected to thetransport lock crank, and movable with the transport lock crank betweenthe transport position and the unlocked position.
 2. The mower deck liftsystem of claim 1 wherein the transport lock indicator extends from thecenter of the height of cut control knob in the transport position. 3.The mower deck lift system of claim 1 wherein the height of cut cam hasa plurality of steps, each step corresponding to a mower deck heightsetting.
 4. The mower deck lift system of claim 1 wherein the height ofcut control knob is connected to the height of cut cam by a tube.
 5. Themower deck lift system of claim 4 wherein the transport lock indicatoris connected to the height of cut control knob by a wire form throughthe tube.
 6. The mower deck lift system of claim 1 wherein the transportlock crank is biased to the transport position.
 7. The mower deck liftsystem of claim 1 further comprising a foot pedal to raise the mowerdeck.
 8. The mower deck lift system of claim 1 further comprising anelectro-hydraulic actuator to raise the mower deck.
 9. A mower deck liftsystem comprising: a height of cut control knob for adjusting the heightof the mower deck; a transport lock that is biased to lock the mowerdeck in a transport position if the mower deck is raised to a maximumheight; and a transport lock indicator extending from the height of cutcontrol knob if the mower deck is locked in the transport position. 10.The mower deck lift system of claim 9 wherein the transport lockcomprises a pivotable transport lock crank attached to the transportlock indicator by a wire form.
 11. The mower deck lift system of claim10 further comprising a spring urging the transport lock crank to lockin the transport position.
 12. The mower deck lift system of claim 9further comprising a foot pedal to raise the mower deck.
 13. The mowerdeck lift system of claim 9 further comprising an electro-hydraulicactuator to raise the mower deck.
 14. (canceled)
 15. (canceled) 16.(canceled)
 17. (canceled)
 18. (canceled)
 19. (canceled)
 20. (canceled)21. A mower deck lift system comprising: a height of cut control knobrotatable to a plurality of positions and connected to a height of cutcam, each position of the knob corresponding to a plurality of cuttingheights listed on the knob between a minimum and a maximum cuttingheight, and causing the cam to rotate to move the mower deck to thecorresponding cutting height; and a transport lock indicator at thecenter of the height of cut control knob having a pointer to the cuttingheights listed on the knob, the indicator being movable between a firstposition if the mower deck is locked in a transport position above themaximum cutting height and a second position if the mower deck is notlocked in the transport position.
 22. The mower deck lift system ofclaim 21 wherein the transport lock indicator is biased to lock themower deck in the transport position if the mower deck is raised to themaximum cutting height.
 23. The mower deck lift system of claim 21wherein in the first position the transport lock indicator extends abovethe height of cut control knob.